1. Field of the Invention
The present invention relates to a free-wheel hub assembly for a bicycle.
2. Description of the Related Art
Referring to FIG. 1, a conventional free-wheel hub assembly is shown to include: a tubular spoke-mounting hub 2 having bowl-shaped left and right ends respectively defining left and right recesses, each of which is confined by a recess-defining wall that has an inner recess portion and an outer recess portion; an axle 1 co-axially extending through the spoke-mounting hub 2 and having a right axle portion 100 disposed outwardly of the right end of the spoke-mounting hub 2; left and right inner bearings 201 sleeved on the axle 1 and disposed at the inner recess portions of the left and right recesses for rotatably mounting of the spoke-mounting hub 2 thereon; a tubular spacing sleeve 6 sleeved on the right axle portion 100 and disposed in the outer recess portion of the right recess; a sprocket-mounting member 3 having an annular coupling end 301 extending into the outer recess portion of the right recess in the spoke-mounting hub 2 and radially spaced apart from the tubular spacing sleeve 6 to define a gap xe2x80x9cGxe2x80x9d therebetween; left and right outer bearings 5 mounted around the right axle portion 100 to facilitate rotation of the sprocket-mounting member 3 on the axle 1; and a ratchet unit 4 disposed in the outer recess portion of the right recess and coupled to the coupling end 301 of the sprocket-mounting member 3 and the recess-defining wall of the right recess in the right end of the spoke-mounting hub 2 so as to permit co-rotation of the sprocket-mounting member 3 and the spoke-mounting hub 2.
One drawback of the aforementioned conventional free-wheel hub assembly resides in that the sprocket-mounting member 3 can move in a radial direction relative to the axle 1 due to the presence of the gap xe2x80x9cGxe2x80x9d which, in turn, can result in unstable mounting of the ratchet unit 4 in the outer recess portion of the right recess in the spoke-mounting hub 2.
Therefore, the object of this invention is to provide a free-wheel hub assembly which includes a self-lubricating bearing that fills the aforementioned gap in such a manner as to provide stable mounting of a ratchet unit in a right end of a spoke-mounting hub of the free-wheel hub assembly.
Accordingly, a free-wheel hub assembly of the present invention includes: a tubular spoke-mounting hub having a bowl-shaped right end defining a right recess that is confined by a recess-defining wall and that has an inner recess portion and an outer recess portion; an axle co-axially extending through the spoke-mounting hub and having a right axle portion that extends through the right recess, and that is formed with an annular axle flange projecting radially and outwardly therefrom into the outer recess portion of the right recess and having an inner end face transverse to an axis of the axle and an outer end face opposite to the inner end face; an inner bearing sleeved slidingly on the right axle portion of the axle, disposed in the inner recess portion of the right recess, and abutting against the inner end face of the annular axle flange; a self-lubricating bearing sleeved on the annular axle flange, and having an inner surface in sliding contact with the annular axle flange and an outer surface opposite to the inner surface; a tubular sprocket-mounting member having an annular coupling end that extends into the outer recess portion of the right recess, and that is sleeved on and that is in sliding contact with the outer surface of the self-lubricating bearing; a ratchet unit disposed in the outer recess portion of the right recess and coupled to the annular coupling end of sprocket-mounting member and the recess-defining wall so as to permit synchronous rotation of the sprocket-mounting member and the spoke-mounting hub in a forward direction; and an outer bearing sleeved on the right axle portion, disposed in the sprocket-mounting member, and abutting against the outer end face of the annular axle flange and the annular coupling end of the sprocket-mounting member so as to permit smooth and synchronous rotation of the spoke-mounting hub and the sprocket-mounting member on the axle.